If you are going to grow tomatoes -- or really any fruit of vegetable -- you are more than likely going to run into some kind of problem. It's just part of the process.
In this blog, I go over 10 different problems you might run into and what you can do to solve them.
1. Small holes in leaves of seedlings – Flea beetles eat small holes in the leaves of tomato seedlings and small transplants. Flea beetles usually focus on seedlings. To prevent this, try and make your tomato seedlings healthy as healthy tomato seedlings can tolerate beetle damage. The entire plant may be destroyed.
2. Leaves eaten off plant – Vegetable weevils or Colorado potato beetles attack many vegetables including tomatoes. They are small and dark in color and do not fly; they are slow to spread. Keep your garden clean and handpick adult beetles off plants. Use rotenone in severe cases.
3. Lower leaves have a bronze, oily color – The tomato russet mite are microorganisms that are not visible to the eye but with the aid of a hand lens. They are whitish-yellow in color and pear-shaped. They cause lower leaves of tomato plants to have a bronze oily color. Treat with sulfur and avoid growing tomatoes near petunias.
4. Tomato leaves are yellowish and slightly curled and with small shiny dots – This is caused by aphids. Aphids are tiny, oval, and yellowish to greenish pear-shaped insects. They colonize on the undersides of tomato leaves and they leave behind sticky excrement known as honeydew, which can turn into a black dirty mold. You can make use of insecticidal soap to take care of them.
5. Leaves turn yellow and then brown from the base of the plant – Plant loses vigor when this happen. This is caused by the root-knot nematode, a microscopic eelworm that attacks feeder roots. Rotate crops. Plant resistant varieties labeled VFN. Remove old plant debris from garden.
6. Leaves appear scorched and wilted – This is caused by leafhoppers. These leafhoppers are brown, green, or yellow bugs. They are ⅓-inch long with wedge-shaped wings. They jump from side to side and suck the juices from plants. To take care of this, use insecticidal soap and cover your tomato plants with floating row covers to exclude leafhoppers.
7. Water-soaked spots on leaves; this leaves spots on leaves and they become circular with gray centers – Septoria leaf spot or leaf spot is a fungus disease. To take care of this, rotate crops, plant resistant varieties, apply liquid copper spray or copper dust every 7 to 10 days, and keep garden free of plant debris.
8. Older leaves turn yellow and die; this yellowing of older leaves begins between main veins of leaves - a soil fungus causes Verticillium Wilt. It favors cool soil and air temperatures. To prevent this, plant resistant varieties (V or VF) and do not plant where tomatoes, potatoes, peppers, cucumber and eggplant family plants have been recently growing. This disease is most obvious in hot weather when the tomato plant is loaded with fruit and with lower amount of water.
9. Round white powdery spots and coating on leaves – Fungal spores cause this powdery mildew. When the humidity is high, the spores germinate on dry leaf surfaces. This type of disease is common in late summer but does not result in loss of plant. To care for this, pick off infected leaves and avoid water stress.
10. Dark brown to black blemishes surrounded by yellowing along edges of the tomato leaves – These bacterial specks grow where the weather is wet and cool with a temperature less than 70°F (21°C). to prevent this, delay planting of tomato seedlings until temperatures warm. Avoid overhead watering and rotate crops.